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Introduction What is ? refers to a family of specifications developed by the IEEE for wireless LAN technology Standards up to 2Mbps (900MHZ) b 2.4GHZ and up to 11Mbps – a 5GHZ and up to 54Mbps. 200x – g 2.4GHZ and up to 54Mbps. 200x – e for QoS.

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Limitation of Distributed Coordination Function (DCF) Does not provide any QoS guarantees. Does not support real-time application. Designed for equal priorities. Does not support the concept of differentiating frames with different user priorities.

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Limitation of Point Coordination Function (PCF) poor QoS performance. Uses a simple round-robin algorithm, which can not handle the various QoS requirements. Transmission time of the polled stations is unknown.

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HCF Controlled Channel Access ( HCCA) Operates in CFP and CP. Provides Guaranteed Services with a much higher probability than EDCA. Combines the advantages of PCF and DCF. Coordinates the traffic in any fashion (not just round- robin).

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Conclusion The IEEE wireless LAN (WLAN) has become one of the most widely used wireless technologies in these days. The standards can not provide any QoS guarantees due to poor performance. The e offers QoS support to time- sensitive applications, such as, audio and video communications.